COMPLICATED BASIC METABOLIC PRODUCTS. 71 



the contradictory results of authors with the Bact. coli 

 (see special part) and the Micr. pyogenes are thus ex- 

 plained. 



What are described in the literature as Micrococcus 

 urese Leube, Bacillus urese Leube, Bacillus urese liquefa- 

 ciens Fliigge, can be partially identified as the Micr. pyo- 

 genes y albus and Bacterium coli, but the descriptions of 

 these varieties allow of no accurate identification. The 

 urea-splitting function appears to occur occasionally in 

 very many varieties. Warington (C. B. vi, 498), Burri, 

 HerfeldtandStutzer (C. B. L. i, 284) have described urea- 

 splitting varieties. Compare also the investigations of Mi- 

 quel (Ann. d. Micrographie, Bd. i u. f. ), which are very 

 interesting biologically, but which lose much in value be- 

 cause Miquel has elaborated a very singular nomenclature 

 which does not talvc into consideration the usual varieties. 

 Miquel has observed varieties which are able to decom- 

 pose as much as 60 gm. of urea to a liter. He claims to 

 have isolated a special ferment, urase, which decomposes 

 urea. 



The older literature can be found as given by Leube 

 (Virchow's Archiv, Bd. c, p. 540); the newer, with the 

 method of determining ammonia (according to Schlosing), 

 by Mann. 



3. Formation of Complicated Basic Metabolic 

 Products. 



Especially through the investigations of Brieger (Ueber 

 Ptomaine, Heft i-iii, Berlin, Hirschwald), besides ammo- 

 nia, a large number of basic, crystalline, nitrogenous 

 bodies are known as products of bacterial metabolism. 

 These bodies are usually called ptomains (-iiTWfia, putrefac- 

 tion) or putrefaction alkaloids. ^ They occur, so far as 

 closely studied, mostly in the following groups : 



^ For a long time the poisonous ptomains were called toxins, yet now 

 most authors call all bacterial poisons toxins, without reference to 

 their chemical constitution, and usually one understands the term to 

 include the " albuminous-like " bacterial poisons more especially. 



